The present invention relates to an arrangement for mounting and adjusting a deflection-coil holder for a cathode-ray tube, and more particularly for a color picture tube of the shadow-mask type, said holder substantially holding in position a ferrite toroidal core and two pairs of coils, one for horizontal and one for vertical deflection, in which a mounting member is connected with the conical portion of the picture-tube envelope, comprising means for mounting and adjusting the deflection-coil holder.
Such arrangements are known, for example, from the German Printed Patent Application (DT-AS) No. 22 24 702. According to this publication, a ring-shaped mounting member is bonded to the conical portion of the picture-tube envelope with the aid of a first adhesive. On this mounting member there are provided at least three stay bolts engaging corresponding openings in the deflection-coil holder. Following the adjustment, the spaces remaining in the openings are filled with a second adhesive. According to one modification of this arrangement, it is proposed that in the ring-shaped mounting member, additionally still the heads of at least three screws are fixed as well with the aid of the first adhesive, with the screw shafts thereof then serving as threaded bolts with the aid of which the adjustment is carried out by means of knurled adjusting wheels and nuts, with the effected adjustment also in this case being fixed with the aid of a second adhesive.
In both cases it is not possible to detach the ring-shaped mounting member and the deflection-coil holder with the deflection system after the adjustment has been carried out and following the bonding, without damaging or destructing at least a part of the envelope, or to separate the parts from one another. This, however, is desirable with a view to the high prices of the picture-tube envelopes, in order to be able to reuse the envelope in cases where it has been found to be faulty. Moreover, a bonding causes intervals during the production process, because after each bonding operation it is necessary to wait until the adhesive has become sufficiently solidified and cured.